New gratings based on phase contrast imaging techniques have been developed to extend the capabilities of x-ray imaging. Radiography has been utilized for over a hundred years, however, the use of gratings based on phase contrast imaging techniques now allows for the detection of phase shifts in addition to absorption. The gratings must be fine enough in pitch to avoid limiting special resolution, and thick enough to absorb x-rays. To meet these criteria, the gratings must be formed or coated with a high x-ray absorbing material at high aspect ratios making the fabrication process challenging. Various processes have been used to fabricate such gratings. One such process is the use of a traditional LIGA process to form gold gratings. The LIGA process uses x-ray lithography to obtain polymer structures with vertical and extremely smooth sidewalls to form gold gratings. Gold gratings made by the LIGA process are functional and structurally rigid, however, LIGA processes are costly and time consuming. Another process utilizes reactive-ion etching (RIE) of silicon to generate high aspect-ratio trenches, for example 1 micron wide and 25-35 microns tall on a 4 micron pitch. RIE of silicon allows for precise and repeatable fabrication of substrates that are transparent to x-rays. The trenches are then coated with a 1 micron thick high density metal creating a 50% duty 1 micron wide, 25-35 micron tall grating. The coating of high aspect-ratio trenches tends to collect at the top of the grating and thin towards the base of the grating due to the depth of the trench. Thus, the resulting layer is neither uniform in thickness nor conformal to the shape of the grating.